In its most basic form, a radio-communication network includes a mobile station, such as a cellular phone, and a base station. The mobile station is in radio-communication with the base station. In turn, the base station is connected to and in communication with a public switched telephone network, which is the fixed network installed in most homes.
To communicate with each other, the mobile station and the base station use antennas. The antennas are used to transmit radio frequency (RF) signals between the mobile station and the base station.
The antenna has a radiating element, and may have a matching structure or element. The radiating element is the portion of the antenna which may be used to radiate the RF signal from one of the mobile station and the base station to the other of the mobile station and the base station. At higher radio frequencies, the matching element may be needed to balance the impedance of the radiating element.
The mobile station antenna typically includes a long rod of circular cross-section. The rod may be used as the radiating element, or the rod may be used as a support for the radiating element. A section of wire, which functions as the matching element, is wrapped about the rod with a layer of dielectric material disposed therebetween. Conventionally, both the rod and the wire are coated with a polymer material for mechanical protection.
The mobile station antenna is typically mounted on a mobile station housing so as to extend through an opening in the housing. The antenna is usually mounted so that it is moveable between a fully retracted position, where only a portion of the antenna projects to outside the housing, and a fully extended position, where a significant portion of the antenna projects to outside the housing.
The above mobile station antennas may have several problems, however. For example, the wire used as the matching element may be susceptible to breakage during the wrapping process. Additionally, the rod element may be susceptible to excessive bending with the antenna in the fully extended position relative to the mobile station housing. Moreover, the size of the antenna in the fully retracted position relative to the housing may be so large as to take up considerable amounts of space within the housing. This is particularly significant because the trend in the cellular phone industry has been to design and manufacture mobile stations of decreasing width, length and depth.